3,155 research outputs found

    Complex maps without invariant densities

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    We consider complex polynomials f(z)=z+c1f(z) = z^\ell+c_1 for 2N\ell \in 2\N and c1Rc_1 \in \R, and find some combinatorial types and values of \ell such that there is no invariant probability measure equivalent to conformal measure on the Julia set. This holds for particular Fibonacci-like and Feigenbaum combinatorial types when \ell sufficiently large and also for a class of `long-branched' maps of any critical order.Comment: Typos corrected, minor changes, principally to Section

    Visualizations of Projected Rainfall Change in the United Kingdom: An Interview Study about User Perceptions

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    Stakeholders from public, private, and third sectors need to adapt to a changing climate. Communications about climate may be challenging, especially for audiences with limited climate expertise. Here, we study how such audience members perceive visualizations about projected future rainfall. In semi-structured interviews, we presented 24 participants from climate-conscious organizations across the UK with three prototypical visualizations about projected future rainfall, adopted from the probabilistic United Kingdom Climate Projections: (1) Maps displaying a central estimate and confidence intervals, (2) a line graph and boxplots displaying change over time and associated confidence intervals, and (3) a probability density function for distributions of rainfall change. We analyzed participants’ responses using “Thematic Analysis”. In our analysis, we identified features that facilitated understanding—such as colors, simple captions, and comparisons between different emission scenarios—and barriers that hindered understanding, such as unfamiliar acronyms and terminology, confusing usage of probabilistic estimates, and expressions of relative change in percentages. We integrate these findings with the interdisciplinary risk communication literature and suggest content-related and editorial strategies for effectively designing visualizations about uncertain climate projections for audiences with limited climate expertise. These strategies will help organizations such as National Met Services to effectively communicate about a changing climate

    Etiology and pathophysiology of chronic transplant dysfunction

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    Integration of a smoking cessation program in the treatment protocol for patients with head and neck and lung cancer

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    Smoking is the main causative factor for development of head and neck and lung cancer. In addition, other malignancies such as bladder, stomach, colorectal, kidney and pancreatic cancer have a causative relation with smoking. Continued smoking after having been diagnosed with cancer has many negative consequences: effectiveness of radiotherapy is diminished, survival time is shortened and risks of recurrence, second primary malignancies and treatment complications are increased. In view of the significant health consequences of continued smoking, therefore, additional support for patients to stop smoking seems a logical extension of the present treatment protocols for smoking-related cancers. For prospectively examining the effect of nursing-delivered smoking cessation programme for patients with head and neck or lung cancer, 145 patients with head and neck or lung cancer enrolled into this programme over a 2-year period. Information on smoking behaviour, using a structured, programme specific questionnaire, was collected at baseline, and after 6 and 12 months. At 6 months, 58 patients (40%) had stopped smoking and at 12 months, 48 patients (33%) still had refrained from smoking. There were no differences in smoking cessation results between patients with head and neck and lung cancer. The only significant factor predicting success was whether the patient had made earlier attempts to quit smoking. A nurse-managed smoking cessation programme for patients with head and neck or lung cancer shows favourable long-term success rates. It seems logical, therefore, to integrate such a programme in treatment protocols for smoking-related cancers

    К численному решению задач о деформации анизотропных пластин с отверстием

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    Представлен подход к расчету напряженно-деформированного состояния пластин с отверстием, основанный на численной параметризации двусвязной области, сведении исходной нелинейной краевой задачи к последовательности линейных двухмерных и интегрировании последних устойчивым численным методом. Исследуется влияние формы и месторасположения отверстия на напряженно-деформированное состояние квадратной пластины.Представлено підхід до розрахунку напружено-деформованого стану пластин, що послаблені отвором. Підхід базується на числовій параметризації двозв’язної області, зведенні вихідної нелінійної задачі до послідовності лінійних двомірних та останніх до одномірних, інтегрування яких проводиться стійким числовим методом. Досліджується вплив форми та місцезнаходження отвору на напружено-деформований стан квадратної пластини.The study presents an approach to stressed-state analysis of plates with apertures which is based on the numerical parameterization of a doubly-connected area, reduction of the initial nonlinear boundary-value problem to a sequence of linear two-dimensional problems and integrating the latter by the stable numerical method. The effect of form and place of an aperture on stressed state of a square plate has been analyzed

    Chytrid epidemics may increase genetic diversity of a diatom spring-bloom

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    Contrary to expectation, populations of clonal organisms are often genetically highly diverse. In phytoplankton, this diversity is maintained throughout periods of high population growth (that is, blooms), even though competitive exclusion among genotypes should hypothetically lead to the dominance of a few superior genotypes. Genotype-specific parasitism may be one mechanism that helps maintain such high-genotypic diversity of clonal organisms. Here, we present a comparison of population genetic similarity by estimating the beta-dispersion among genotypes of early and peak bloom populations of the diatom Asterionella formosa for three spring-blooms under high or low parasite pressure. The Asterionella population showed greater beta-dispersion at peak bloom than early bloom in the 2 years with high parasite pressure, whereas the within group dispersion did not change under low parasite pressure. Our findings support that high prevalence parasitism can promote genetic diversification of natural populations of clonal hosts

    An item and construct bias analysis of two language versions of a verbal analogies scale

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    The Woodcock Muñoz Language Survey is a test of cognitive academic language proficiency that has been adapted from English into Xhosa by a South African team of researchers. This study was primarily concerned with the Verbal Analogies Scale of the Woodcock Muñoz Language Survey and aimed to extend previous research on the equivalence of the two language versions of the scale. The study employed a monolingual two-group design consisting of 150 mainly English-speaking and 149 mainly Xhosa learners in Grades 6 and 7. The first research objective was to investigate item bias (or differential item functioning items) in the Visual Analogies Scale across the Xhosa and English versions using logistic regression and Mantel–Haenszel statistical techniques. Five items were identified as differential item functioning. The second objective was to evaluate the construct equivalence of the two versions by conducting a factor analysis after removing the differential item functioning items from the scale. Two factors were identified. The first factor displayed significant loadings across both language versions. The second factor was stable for the English version but not for the Xhosa version. Results were supported by calculating a Tucker’s phi coefficient for both factors. It was therefore concluded that Factor 1 is structurally equivalent across the two language versions but that Factor 2 was not structurally equivalent. Thus, the detection and removal of differential item functioning items did not result in structural equivalence.Department of HE and Training approved lis

    Гарантоздатність як фундаментальний узагальнюючий та інтегруючий підхід

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    Представлені головні принципи та умови становлення і етапи розвитку фундаментальної теорії і практики узагальнюючих та інтегруючих концепцій гарантоздатності, починаючи з першої об’єднаної конференції двох наукових шкіл Дж. фон Неймана і Н. Вінера. Приведені основні положення розвитку теоретичних засад і результатів прикладних досліджень інтеграційних процесів безвідмовності (надійності), відмовостійкості та гарантоздатності інформаційно-управляючих комп’ютерних систем (ІУКС).Представлены главные принципы, условия становления и этапы развития фундаментальной теории и практики обобщающих и интегрирующих концепций гарантоспособности, начиная с первой объединённой конференции двух научных школ Дж. фон Неймана и Н. Винера. Приведены основные положения развития теоретических основ и результатов прикладных исследований интеграционных процессов безотказности (надёжности), отказоустойчивости и гарантоспособности информационно-управляющих компьютерных систем (ИУКС).The main principles and conditions of formation and stages of development of the fundamental theory and practice of the generalizing and integrating concepts of dependability were presented after the leadthrough the first joint conference of two scientific schools of J. von Neumann and N. Wiener. The basic aspects of development of theoretical principles and results of applied researches of integration processes of reliability (fail-safety)

    High DNMT1 Is Associated With Worse Local Control in Early-Stage Laryngeal Squamous Cell Carcinoma

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    OBJECTIVES/HYPOTHESIS: Early-stage laryngeal squamous cell carcinoma (LSCC) has yielded local control rates of 75% after radiotherapy. DNA methylation, in which DNA methyltransferases play an important role, has influence on tumorigenesis. In this study, we investigated the association between the expression of DNA methyltransferase 1 (DNMT1) and local control in early-stage LSCC treated with radiotherapy. STUDY DESIGN: Retrospective cohort study. METHODS: We analyzed a well-defined homogeneous series of 125 LSCC patients treated with radiotherapy with curative intent. The association of immunohistochemical expression of DNMT1 with local control was evaluated using Cox proportional hazard regression models. RESULTS: With a median follow-up of 58 months, 29 local recurrences (23%) were observed. On univariate analysis, worse local control was associated with high DNMT1 expression (hazard ratio [HR] 2.57, 95% confidence interval [CI] 1.10-6.01). Also, higher T-stage (HR 2.48, 95% CI 1.06-5.80) and positive N-status (HR 2.62, 95% CI 1.06-6.47) were associated with worse local control. Multivariate Cox regression demonstrated that high DNMT1 (HR 2.81; 95% CI 1.20-6.58) was independently associated with worse local control. CONCLUSIONS: We found an association between high DNMT1 expression and worse local control in a homogeneous well-defined cohort of early-stage LSCC patients treated with definitive radiotherapy. The association between DNA methylation status as determined by DNMT1 expression and local control suggests that DNMT1 acts as a potential prognostic tumor marker in treatment decision-making in early-stage laryngeal carcinoma. LEVEL OF EVIDENCE: NA Laryngoscope, 2021
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